This invention is directed to a protective overcap commonly applied over a primary drum dispensing closure.
In the drum industry it has long been the common practice to equip filled and closed drums with a protective overcap applied over the primary dispensing closure. Heretofore such protective overcaps made of metal or a combination of metal and plastic, were crimped onto the upstanding neck surrounding the threaded dispensing opening. While these crimped on drum seals performed satisfactorily for their intended function, they had certain shortcomings when viewed in the light of present day market conditions. For example, these crimped on seals were applied with either a manual or power operated crimping tool specially designed for that purpose. These tools are relatively costly and rather cumbersome to use under continuous production conditions. The current trend is clearly toward ease of application taking advantage of any possible cost savings in terms of labor and equipment.
In addition, crimped on seals without exception are either formed entirely of metal or incorporate a metal collar of some sort to support the crimping action. This metal presence necessitates some form of metal cutting or tearing action to enable authorized removal of the seal from the underlying closure. Regardless of the degree of care exercised in the removal operation, the possibility of misstep is always present. Any cut finger hazard, real or perceived, is in today's world looked upon as a significant negative. Thus both safety of removal and ease of removal are now very much sought after.
As a consequence a number of all plastic overcaps adapted for application to drum closures have recently been brought forward. Each of these has to date, however, exhibited one deficiency or another when used under actual field conditions. The need for ease of application of an all plastic closure overcap requires sufficient flexibility to enable unassisted, single-handed seating of the overcap on the closure neck protruding from the top of a 55 gallon drum. This seemingly minor operation has a significant effect on drum filling efficiency. At the same time subsequent authorized removal of the overcap must be achievable with relative ease, unaided without the use of any tool, knife or the like. In addition, such authorized removal must effect some obvious destruction of the overcap construction or a part thereof in order to thwart any spurious reapplication of the part. Any undetectable tampering or pilferage is thus averted.